Low-efficacy HIV vaccines: potential for community-based intervention programmes

Anderson, Roy M.; Gp, Garnett

doi:10.1016/s0140-6736(96)07100-0

Cited by 68 publications

(53 citation statements)

References 14 publications

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“…For one, initial HIV vaccines are likely to be only partially efficacious [8,9]. High levels of vaccine uptake among communities at risk for HIV infection will be required to achieve effective reduction of HIV transmission with low to moderate efficacy vaccines [10,11]. Yet a recent WHO-UNAIDS panel of experts estimated future global HIV vaccine uptake at only 38% of the projected need in the case of vaccines with high (>70%) efficacy and only 19% of projected need in the case of vaccines with low to moderate (30-50%) efficacy [12].…”

Section: Introductionmentioning

confidence: 99%

“…A qualitative study among high-risk communities in Los Angeles suggests that concerns about low to moderate efficacy HIV vaccines and fears of physical side effects may decrease vaccine acceptability [25]. The possible role of other vaccine attributes on acceptability, such as cross-clade protection and duration of protection, both key elements in vaccine effectiveness on an epidemic level [10], have not been studied.…”

Section: Introductionmentioning

confidence: 99%

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HIV vaccine acceptability among communities at risk: The impact of vaccine characteristics

Newman

Duan²,

Lee³

et al. 2006

Vaccine

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HIV vaccines offer the best long-term hope of controlling the AIDS pandemic; yet, the advent of HIV vaccines will not ensure their acceptability. We conducted a cross-sectional survey (n = 143), incorporating conjoint analysis, to assess HIV vaccine acceptability among participants recruited using multi-site (n = 9), venue-based sampling in Los Angeles. We used a fractional factorial experimental design to construct eight hypothetical HIV vaccines, each with seven dichotomous attributes. The acceptability of each vaccine was assessed individually and then averaged across participants. Next, the impact of each attribute on vaccine acceptability was estimated for each participant using ANOVA and then analyzed across participants. Acceptability of the eight hypothetical HIV vaccines ranged from 33.2 (S.D. 34.9) to 82.2 (S.D. 31.3) on a 0-100 scale; mean = 60.0 (S.D. 21.9). Efficacy had the greatest impact on acceptability (22.7; CI: 18.5-27.1; p < 0.0001), followed by cross-clade protection (12.5; CI: 8.7-16.3, p < 0.0001), side effects (11.5; CI: 7.4-15.5; p < 0.0001), and duration of protection (6.1; CI: 3.2-9.0; p < .0001). Route of administration, number of doses and cost were not significant. Low acceptability of "partial efficacy" vaccines may present obstacles to future HIV vaccine dissemination. Educational and social marketing interventions may be necessary to ensure broad HIV vaccine uptake.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

HIV vaccine acceptability among communities at risk: The impact of vaccine characteristics

Newman

Duan²,

Lee³

et al. 2006

Vaccine

View full text Add to dashboard Cite

show abstract

“…Over the past few decades, a large number of simple compartmental mathematical models of the general form SVI or SVIR (where S, V, I and R denote the populations of susceptible, vaccinated, infectious and recovered individuals) have been used in the literature to assess the impact or potential impact of imperfect vaccines for combatting the spread of some human diseases (see, for instance, [1,3,4,6,16,17,18,20,24,25,26,35,37] and the references therein). While in some of these studies (e.g., [3,6,16,17,37]) the vaccine is only given to people newly recruited into the population, such as newborns (cohort vaccination), in many others (e.g., in [1,20,26,35]), a proportion of susceptible individuals is continuously vaccinated.…”

mentioning

confidence: 99%

“…While in some of these studies (e.g., [3,6,16,17,37]) the vaccine is only given to people newly recruited into the population, such as newborns (cohort vaccination), in many others (e.g., in [1,20,26,35]), a proportion of susceptible individuals is continuously vaccinated. In other studies, such as Arino et al [4], both cohort and continuous vaccination are provided.…”

mentioning

confidence: 99%

An sveir model for assessing potential impact of an imperfect anti-SARS vaccine

Gumel

McCluskey

Watmough

2006

Mathematical Biosciences and Engineering

105

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Abstract. The control of severe acute respiratory syndrome (SARS), a fatal contagious viral disease that spread to over 32 countries in 2003, was based on quarantine of latently infected individuals and isolation of individuals with clinical symptoms of SARS. Owing to the recent ongoing clinical trials of some candidate anti-SARS vaccines, this study aims to assess, via mathematical modelling, the potential impact of a SARS vaccine, assumed to be imperfect, in curtailing future outbreaks. A relatively simple deterministic model is designed for this purpose. It is shown, using Lyapunov function theory and the theory of compound matrices, that the dynamics of the model are determined by a certain threshold quantity known as the control reproduction number (Rv ). If Rv ≤ 1, the disease will be eliminated from the community; whereas an epidemic occurs if Rv > 1. This study further shows that an imperfect SARS vaccine with infection-blocking efficacy is always beneficial in reducing disease spread within the community, although its overall impact increases with increasing efficacy and coverage. In particular, it is shown that the fraction of individuals vaccinated at steady-state and vaccine efficacy play equal roles in reducing disease burden, and the vaccine must have efficacy of at least 75% to lead to effective control of SARS (assuming R 0 = 4). Numerical simulations are used to explore the severity of outbreaks when Rv > 1.

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“…Previous models have provided insights into the effects of antiretroviral therapy, as well as partially effective vaccines (which induce sterilizing immunity in only a proportion of vaccinated individuals), live attenuated vaccines, and therapeutic vaccines or immunotherapies administered to infected individuals (3,5,15,16,18,19,45). The CTL-inducing vaccines currently being tested in monkeys appear unable to prevent infection, but instead appear able to modify the subsequent course of disease.…”

mentioning

confidence: 99%

Predicting the Impact of a Nonsterilizing Vaccine against Human Immunodeficiency Virus

Davenport

Ribeiro

Chao

et al. 2004

J Virol

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Studies of human immunodeficiency virus (HIV) vaccines in animal modelssuggest that it is difficult to induce complete protection from infection (sterilizing immunity) but that it is possible to reduce the viral load and to slow or prevent disease progression following infection. We have developed an age-structured epidemiological model of the effects of a disease-modifying HIV vaccine that incorporates the intrahost dynamics of infection, a transmission rate and host mortality that depend on the viral load, the possible evolution and transmission of vaccine escape mutant viruses, a finite duration of vaccine protection, and possible changes in sexual behavior. Using this model, we investigated the long-term outcome of a disease-modifying vaccine and utilized uncertainty analysis to quantify the effects of our lack of precise knowledge of various parameters. Our results suggest that the extent of viral load reduction in vaccinated infected individuals (compared to unvaccinated individuals) is the key predictor of vaccine efficacy. Reductions in viral load of about 1 log 10 copies ml ؊1

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Low-efficacy HIV vaccines: potential for community-based intervention programmes

Cited by 68 publications

References 14 publications

HIV vaccine acceptability among communities at risk: The impact of vaccine characteristics

HIV vaccine acceptability among communities at risk: The impact of vaccine characteristics

An sveir model for assessing potential impact of an imperfect anti-SARS vaccine

Predicting the Impact of a Nonsterilizing Vaccine against Human Immunodeficiency Virus

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